Sewing machine for the formation of a rectangular stitch pattern

ABSTRACT

A sewing machine for the formation of an endless stitch pattern has a two-part clamping frame including an outer main frame and an inner clamp member along the closing side of the pattern. Means are provided for horizontally displacing the auxiliary clamp member to clear the stitching line upon closure of the pattern.

United states Patent Nicolay v 1151 3,669,043 1 June 13, 1972 I 1541 SEWING MACHINE FOR THE FORMATION OF A RECTANGULAR STITCH PATTERN [72] Inventor: Karl Nicolay, Biele feld, Germany 22 Filed: Nov. 4, 1970 21 Appl.No.: 86,836

[30] Foreign Application Priority Data Nov. 6,1969 Germany ..P 19 55 796.1

52 U.S.Cl...' .Q ..ll2/76,ll2/ll4 s1 1m.c|...'. ..1105113/12 58 Field ofSearch ...1 2/76, 77, 70, 65, 104, 114

[56] References Cited.

UNITED s ATEs PATENTS 1,739,059 12/1929 Carlson ..ll2/76 l,85 6,900 5/1932 Allen ..ll2/76 2,849,971 9/1958 Sweetetal ..ll2/76 Primary Examiner-H. Hampton Hunter Attorney-Karl F. Ross ABSTRACT A sewing machine for the formation of an endless stitch pattern has a two-part clamping frame including an outer main frame and an inner clamp member along the closing side of the pattern. Means are provided for horizontally displacing the auxiliary clamp member to clear the stitching line upon closure of the pattern.

10 Claims, 5 Drawing Figures PATENTEDJUH 13 m2 SHEET 10F 2 Karl Nicolay INVENTOR.

Attorney SEWING MACHINE FOR THE FORMATION OF A RECTANGULAR STITCH PATTERN My present invention relates to a sewing machine for automatically stitching a closed pattern or stitch group and, more particularly, to a machine for stitching the periphery of labels, belt and hanging loops and, in general, rectangular stitch patterns.

It has been proposed heretofore to machine adapted to produce a closed stitch pattern, e.g. along the periphery of a rectangle, for the stitching of labels, belt loops and garment-hanging loops onto prepared garments, fabric to be transformed intogarments or other merchandise and in the formation of the labels,loops and the like." For the mostp'art, the prior-art systems for the purpose provided a frame to replace the pressure foot of the sewing machine and retain the fabric against a transport plate, while forming therewith a clamp. The stitching of the rectangular pattern was carried out along the inner periphery of this frame which was displaced horizontally relative to the stitching location by a cam arrangement coupled with the needle drive. Means was provided to raise and lower the clamping frame to enable the fabric to be inserted between this clamping member and the underlying plate or to be removed from the fabric clamp.

These systems have been found, however, to have an important disadvantage in that the requirement for stitching internally of the frame in a closed pattern prevented the machine from accommodating folded-over edge strips in, for example, the closing. portion of the pattern. Furthermore, it was not possible to stitch over an edge of the article as is frequently desired. Consequently, conventional machines were of limited utility and were insufficiently versatile to accommodate labels and the like withturned-over edges or adapted to be stitched over such edges. i v i It is the principal object of the present invention to provide a sewing machine of the character described wherein the aforementioned disadvantages can be obviated.

Another'object of this invention is to provide an improved sewing machinefor stitching an endless, preferably rectangular, pattern which will accommodate folded-over edges of the I article as well as overstitching of the edge of the article.

'Still another object of the'invention isto provide an improved fabric-clamping arrangement for a sewing machine of the character described which enablesa stitch seam to'be formed along the edge portion of a closed stitch pattern for a label, belt or hanging loop, orthe like.' 7 v These objects and others which will become apparent hereinafter, are attained, in accordance with the present invention, in a sewing machine'havinga main fabric clamp for displacing the fabric along a substantially closed path in order to form 'thereon a substantially endless stitch pattern, preferably of rectangular configuration, According to the principles of the present invention, this fabric clamp cornprises a main or outer clamp member engageable with the fabric along the outer periphery' of the stitch pattern to be formed and, along the terminal or closing portion of the pattern, i.e'. the portion of the pattern at which the row of stitches is carried to the starting location, a resiliently clamping 'bar is retractable horizontally to clear the end of the article and permit stitch formation along this edge as has been described.

More specifically, the invention relates to a stitch-group sewing machine for the sewing of labels or the like to an underlying fabric or in. theformation of a rectangular seam therearound, which comprises means enabling an edge cover ing or edge-stitching seam to be formed without interruption of the closed-stitch pattern. To this end, the pressure or presser foot of the fabric clamp is so constructed and arranged that the'edge of the article which is to be overstitched is freed from the pressure'foot when this edge reaches the stitching location, The pressure foot of the clamp, therefore, is constructed in two parts including a vertically shiftable'outer main foot and, along the edge to be overstitched, an inner vertically shiftable auxiliary footwhich automatically, prior to closure of the stitch pattern, is withdrawn horizontally. Advantageously, the auxiliary foot is mounted upon the means for displacing provide a sewing the main pressure foot via a bell-crank lever and is provided with detent means for releasably locking the auxiliary pressure or presser foot in engagement with the fabric for joint movement with the main pressure foot during all of the pattern except the closing stitch.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a side-elevational view, partly in diagrammatic form, of a sewing machine embodying the present invention;

FIG. 2 is a detail view of the auxiliary clamp according to the invention;

FIG. 3 is a view similar to FIG. 2 another position;

FIG. 4 is a further detail view illustrating the position of the auxiliary clamp in its withdrawn state for the stitching of the closing stretch of the pattern; and

FIG. 5 is a fragmentary end view in arrow V in FIG. 1.

In the drawing, I show a sewing machine of the cantileveredarm type which comprises the usual post orstand 6, mounted upon a table 6a forming the stitching plate 4and constituted within arm 5 underlying the arm 6b carrying the head 18 of the machine. At the stitching location, a needle 28a is vertically reciprocable in a needle'holder 28 adjacent the usual vertically shiftable rod 17 associated .with the presserfoot. The machine 6, 6b, 18 is provided with the conventional drive by which a motor rotates a cam to verticallyshift the needle holder and thereby forms stitches upon each penetration of the fabric by the needle. A'stitch-formin'g mechanism may be provided in the conventional manner below the stitching plate. All of this mechanism including the means for vertically shifting the pressure rod 17 is conventional in such arm-type sewing machines and is not material to the present invention.

According to the principles of the present invention, a

showing the clamp in the direction of the fabric-displacing device is provided for 'moving the article relative to the stitching location in a closed pattern, e.g. a rectangle to stitch the label, belt loop,han ger loop or the like along the four sides of a rectangular. pattern. This means includes a horizontally shiftable slider 1, which is displaceable parallel to the longitudinal axis of the'machin e, i.e. in the directionof arrow A upon the worktable 4 and carrying, at its forward end, an article-support plate 2, having a horizontal portion 2a overlying the stitch plate of the sewing machine and having the configuration of a frame open toward the righthand side of the machine. The frame 2a, therefore, has a central opening which clears the stitching location in all positions of the fabric clamp. The frame memberZa is carried by arms 2b forming leaf springs which retain the horizontal portion 2a against the worktable of the sewing machine and clamped by an upper member la onto the slider l. The latter is guided at 4a upon the table 4 and carries at its rearward end a saddleshaped or stirrup member 3 having an upstanding portion 3a rising within the space6c overhang by the arm 6b. The" stirrup member further includes a horizontal portion 3b running at right angles to the upstanding portions 3a and extending forwardly, as well as a downwardly and forwardly inclined portion 30 reaching downwardly toward the stitching location but terminating short thereof above the article-carrying member 2 of the clamp.

On the post 6 of the sewing machine, I provide a forkshaped (bifurcated) head 7 which is swingable about a vertical axis defined by a pivot rod 8 and engages a, rearwardly extending projection 3d of the stirrup 3. The swinging movement of t the head 7 is controlled by a cam coupled with the driving mechanism of the needle 28 and defining the pattern in terms of the lengths of the sides of the rectangular pattern and the feed along each side per stitch (stitch length) in the conventional manner. A pin 9 links the head '7 with the projection 3d. The cam controlling the aforementioned relationships is, as is also conventional, replaceable so that these relationships may be charged at will.

At its forward end 3c, the stirrup-shaped arm 3 is provided with a pair of throughgoing horizontal shafts and 11 which reach to opposite sides of the arm and carry, along the opposite flanks thereof, vertical guide plates 12 having slots 10' and 1 1' by which the plates are guided for movement upon the arm 3, the shafts 10 and 11 extending through these slots. The slots 10' and 1 l are mutually parallel but are horizontally spaced to prevent canting of the plates on the arm and the plates are held against the flanks of the arm by dished-disk spring plates 10a and 10b, such that vertical movement of the plates relative to the arm is retarded slightly by friction. A torsion spring 13 in the form of a spring rod is likewise stirrupshaped and has a vertical portion 13a extending upwardly from a circular loop 1312 around a boss 13c mounted upon the upstanding portion 3a of the arm by a screw 33 The other end 13d of the loop is fixed to the arm by a sleeve 14. The vertical portion 13a of the torsion spring 13 extends via a right-angle bend into a horizontal stretch 13e lying parallel to the horizonal portion 3b of the arm. At its forward end, the stretch 13e of the torsion spring is inclined downwardly at 13f and has a horizontal finger 13g bearing upon a pin 15 via a roller 15a contoured to accommodate the finger 13g. The pin 15 and the roller 15a are carried by the plates 12.

At their lower ends, the plates 12 are formed with a pressure foot 16, hereinafter referred to as the main pressure foot, which co-operates with the plate 2 to form a clamp for the portion of the article to be stitched. The main pressure foot 16 may form the three sides of a frame leaving the rearward portion open as indicated earlier.

The presser foot rod 17 of the machine of the present invention is provided with a clamp 19a carrying a lever 19 which engages beneath a pair of forwardly projecting noses 20, respectively provided on the plates 12 to enable the plates and the main pressure foot 16 to be lifted against the force of torsion spring 13 to release the clamp.

Between the guide plates 12, 1 provide an arm 21 which carries, at its forward end, the auxiliary pressure foot 22 fortning the frame portion along the closing stretch of the pattern and hereinafter referred to as the auxiliary foot. The arm 21 is pivotally mounted at 24 via a collar screw to the depending arm 23a of a bell-crank lever 23. The bell-crank lever 23 is, in turn, swingably mounted by a collar screw 25 to the horizontal portion 3b of the arm 3. A coil-type tension spring 26 has one end anchoredin a hole 26a in arm 23a and another end engaging a pin 26b fixed to a generally triangular plate 27 which is pivoted on the upright portion 3a of the arm 3 via the collar screw 3e. The plate 27 is angularly adjustable on the arm 3 and, to this end, is provided with an articulated slot 27a with a center of curvature at 3e in which a screw 27b is received. The screw 27b is threaded into the arm 3 so that, upon tightening of the screw, the plate 27 is clamped in its desired angular position.

The toothed sole of the main foot 16 is so constructed that it lies outwardly on three sides of the stitch pattern to be formed on the article while the sole ofthe auxiliary foot 22 may lie inwardly of the stitch pattern in the engaged position of this member, but is drawn outwardly (FIG. 4) to clear the needle when the last stretch of the pattern is to be formed.

A further bell-crank lever 29 is mounted by a collar screw 30 pivotally upon the plate 27 and has an arm 29' formed with a right-angle cutout 29a adapted to engage a square-head abutment 31 fixed to the arm 23a of bell-crank lever 23. The other arm 29" of the bell-crank lever 29 is engageable by a release pin 32 which is operated by the cam driving member 7 to swing the bell-crank lever 29 in the clockwise sense and release the pin 31, thereby enabling the spring 26 to draw the bell-crank lever 23 in the clockwise sense about its fulcrum 25 and withdraw member 22 to clear the final stretch of the sewing seam or line. Members 29, 29, 29", therefore, constitute a detent for retaining the auxiliary foot 22 in its engaged position. A torsion spring 33 of horseshoe configuration engages the arm 29 to urge the lever 29 in the counterclockwise sense. Alternatively, the release pin 32 can co-operate with the slide 1 to trigger withdrawal of the auxiliary foot 22.

On the underside of the arm 21, l mount, via a bracket 35a, a lead spring 35 having a stop 35 along its upper surface for engagement with a folded edge of the article W to be stitched. Beyond the stop 35', the leaf spring 35 forms the underportion 35" of an auxiliary clamp. The workpiece W is here a label.

The system described above operates as follows:

In the starting position of the machine, the main foot 16 and the auxiliary foot 22 are elevated (FIG. 2) since the pressure lever 19 is in its upper position and retains the plates 12 upwardly against the force of spring 13. A torsion spring 34 coupling the arm 21 with the plates 12 entrains the arm with the plates in upward movement. During such upward movement, the bell-crank lever 23 is rotated in the clockwise sense so that the detent 29' can engage the pin 31 under the force of spring 33. The auxiliary foot 22 is thus moved to the left in the position illustrated in FIG. 2. Between the plate 2 and the main foot 16, the workpiece W to be sewn is inserted and also brought into the clamp formed between members 35" and 22. When the machine is now started, the rod 17 is urged downwardly, whereby spring 13 lowers the plates 12 to bias both pressure feet 16 and 22 downwardly before commencement of the sewing cycle. At the beginning of the sewing cycle, the needle enters the rearleft corner of the label, as seen by an operator sitting directly in front of the arm 6b and hence facing in the direction of arrow V, while the clamp 16, 2 moves with the clamp 22, 35" rearwardly (i.e. to the right in FIG. 1). The position of the auxiliary clamp 22 during this movement is shown in FIG. 3, when the needle reaches the front left corner of the label, with a stitch number and length determined by the aforementioned cam, the clamps and label are moved transversely to bring the front right corner of the label beneath the needle 28a. The clamps and label are then moved upwardly (to the left of FIG. 1) until the stitching location coincides with the rear right corner of the label.

Prior to the commencement of the last sewing stretch, i.e. from the right rear corner to the left rear corner of the label, the release pin 32 trips the detent 29 to withdraw the arm 29 from pin 31 and permit the spring 26 to draw the arm 21 and the auxiliary foot 22 to the right, i.e. rearwardly of the transverse edge to be sewn. Hence the foot 22 clears the last edge of the label and does not impede overstitching of the latter.

The improvement described and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the invention except as limited by the appended claims.

I claim:

1. In a sewing machine for stitching a rectangular pattern in a workpiece and having a stitching location, a presser-foot control and a cam-driven workpiece-displacement mechanism, the improvement which comprises, in combination, a main presser foot operatively connected with said mechanism and engageable with an article around three sides of a rectangular pattern to be stitched thereon for shifting the workpiece relative to said location along the configuration of the pattern, an auxiliary presser foot engageable with the workpiece along the fourth side of the pattern and engageable with said main presser foot during the stitching of the pattern prior to stitching of said fourth side, and means operatively connected with said auxiliary presser foot for withdrawing same from said fourth side during the stitching thereof.

2. The improvement defined in claim 1, further comprising releasable detent means for retaining said auxiliary presser foot in engagement with said workpiece during the stitching of said three sides and a release pin engageable with said detent upon conclusion of the stitching of said three sides for withdrawing said auxiliary presser foot during the stitching of said fourth side.

3. The improvement defined in claim 2 wherein said auxiliary presser foot forms part of a clamp gripping said workpiece.

4. The improvement defined in claim 3 wherein said main presser foot is provided with a slide having a fabric-receiving plate shiftable relative to said location, a stirrup-shaped arm mounted on said slide remote from said location and having an end overhanging said plate, guide means vertically shiftable on said arm, and a pressure member overlying said plate and mounted on said guide means for clamping said workpiece against said plate along said three sides and outwardlyithereof.

5. The improvement defined in claim 4 wherein said auxiliary presser foot is swingably mounted on said arm and said detent' includes at least one bell-crank lever lockingly engageable with said auxiliary presser foot for retaining same in engagement with said workpiece along said fourth side prior to engagement of said pin with said bell-crank lever.

6. The improvement defined in claim 5, further comprising another bell-crank lever fulcrumed on said arm and provided with a square-head pin, the first-mentioned bell crank lever having a recess engageable with said square-head pin, a torsion spring angularly biasing said first bell-crank lever into engagement with said square-head pin, said release pin being engageable with said first bell-crank lever to swing the same to disengage it from said square-head pin, and a spring angularly biasing said other bell-crank lever in a direction tending to withdraw said auxiliary presser foot from said fourth side against the restraint of said detent.

7. The improvement defined in claim 6 wherein said presser foot is mounted on a bar articulated to said other bell-crank lever, said improvement further comprising a torsion spring between said bar and said guide means for yieldably coupling said bar with said guide means, and a further torsion spring mounted on said arm and engaging said guide means for urging said main presser foot out of engagement with said workpiece.

8. The improvement defined in claim 7, further comprising a leaf spring mounted on said bar and extending beneath said auxiliary presser foot for forming a clamp therewith.

9. The improvement defined in claim 8 wherein said presser foot control comprises a vertically shiftable rod and a lever carried by said rod and engaging said guide means for shifting same against the force of said other torsion spring.

10. The improvement defined in claim 9 wherein said guide means includes a pair of guide plates flanking said arm. 

1. In a sewing machine for stitching a rectangular pattern in a workpiece and having a stitching location, a presser-foot control and a cam-driven workpiece-displacement mechanism, the improvement which comprises, in combination, a main presser foot operatively connected with said mechanism and engageable with an article around three sides of a rectangular pattern to be stitched thereon for shifting the workpiece relative to said location along the configuration of the pattern, an auxiliary presser foot engageable with the workpiece along the fourth side of the pattern and engageable with said main presser foot during the stitching of the pattern prior to stitching of said fourth side, and means operatively connected with said auxiliary presser foot for withdrawing same from said fourth side during the stitching thereof.
 2. The improvement defined in claim 1, further comprising releasable detent means for retaining said auxiliary presser foot in engagement with said workpiece during the stitching of said three sides and a release pin engageable with said detent upon conclusion of the stitching of said three sides for withdrawing said auxiliary presser foot during the stitching of said fourth side.
 3. The improvement defined in claim 2 wherein said auxiliary presser foot forms part of a clamp gripping said workpiece.
 4. The improvement defined in claim 3 wherein said main presser foot is provided with a slide having a fabric-receiving plate shiftable relative to said location, a stirrup-shaped arm mounted on said slide remote from said location and having an end overhanging said plate, guide means vertically shiftable on said arm, and a pressure member overlying said plate and mounted on said guide means for clamping said workpiece against said plate along said three sides and outwardly thereof.
 5. The improvement defined in claim 4 wherein said auxiliary presser foot is swingably mounted on said arm and said detent includes at least one bell-crank lever lockingly engageable with said auxiliary presser foot for retaining same in engagement with said workpiece along said fourth side prior to engagement of said pin with said bell-crank lever.
 6. The improvement defined in claim 5, further comprising another bell-crank lever fulcrumed on said arm and provided with a square-head pin, the first-mentioned bell crank lever having a recess engageable with said square-head pin, a torsion spring angularly biasing said first bell-crank lever into engagement with said square-head pin, said release pin being engageable with said first bell-crank lever to swing the same to disengage it from said square-head pin, and a spring angularly biasing said other bell-crank lever in a direction tending to withdraw said auxiliary presser foot from said fourth side against the restraint of said detent.
 7. The improvement defined in claim 6 wherein said presser foot is mounted on a bar articulated to said other bell-crank lever, said improvement further comprising a torsion spring between said bar and said guide means for yieldably coupling said bar with said guide means, and a further torsion spring mounted on said arm and engaging said guide means for urgIng said main presser foot out of engagement with said workpiece.
 8. The improvement defined in claim 7, further comprising a leaf spring mounted on said bar and extending beneath said auxiliary presser foot for forming a clamp therewith.
 9. The improvement defined in claim 8 wherein said presser foot control comprises a vertically shiftable rod and a lever carried by said rod and engaging said guide means for shifting same against the force of said other torsion spring.
 10. The improvement defined in claim 9 wherein said guide means includes a pair of guide plates flanking said arm. 